INTERNATIONAL UNION UNION OF RADIO-SCIENTIFIQUE RADIO SCIENCE INTERNATIONALE ISSN 1024-4530 Bulletin No 323 December 2007 Radio Science Publié avec laide financière de lICSU URSI, c/o Ghent University (INTEC) St.-Pietersnieuwstraat 41, B-9000 Gent (Belgium) The Contents Editorial .......................................................................................................................3 Letter to the Editor ..................................................................................................... 4 In Memoriam .............................................................................................................. 5 Reactance-Domain Signal Processing for Adaptive Beamforming and Direction-of-Arrival Estimation: An Overview ................................................. 14 Wireless Communications: 2020 ............................................................................. 26 Radio Science Doctoral Abstracts ........................................................................... 36 Conferences ............................................................................................................... 38 News from the URSI Community ........................................................................... 40 International Geophysical Calendar 2008 .............................................................. 42 List of URSI Officials ............................................................................................... 47 Information for authors ........................................................................................... 73 Front cover: On top: The technology adoption curve (Source: Ofcom), See the paper by E. Taillefer and J. Cheng (pp. 14-25); Below: A photo of a fabricated seven-element ESPAR antenna operating in the 2.4 GHz band , See the paper by W. Webb (pp.26-35). EDITOR-IN-CHIEF EDITORIAL ADVISORY BOARD EDITOR URSI Secretary General François Lefeuvre W. Ross Stone Paul Lagasse (URSI President) 840 Armada Terrace Dept. of Information TechnologyW. Ross Stone San Diego, CA92106 Ghent University PRODUCTION EDITORS USA St. Pietersnieuwstraat 41 Inge Heleu Tel: +1 (619) 222-1915 B-9000 Gent Inge Lievens Fax: +1 (619) 222-1606 Belgium SENIOR ASSOCIATE EDITOR E-mail: [email protected] Tel.: (32) 9-264 33 20 J. Volakis Fax : (32) 9-264 42 88 P. Wilkinson (RRS) E-mail: [email protected] ASSOCIATE EDITOR FOR ABSTRACTS P. Watson ASSOCIATE EDITORS For information, please contact : P. Banerjee (Com. A) K.L. Langenberg (Com. B) The URSI Secretariat M. Chandra (Com. F) R.P. Norris (Com. J) c/o Ghent University (INTEC) C. Christopoulos (Com. E) T. Ohira (Com. C) Sint-Pietersnieuwstraat 41, B-9000 Gent, Belgium G. DInzeo (Com. K) Y. Omura (Com. H) Tel.: (32) 9-264 33 20, Fax: (32) 9-264 42 88 E-mail: [email protected] I. Glover (Com. F) M.T. Rietveld (Com. G) http://www.ursi.org F.X. Kaertner (Com. D) S. Tedjini (Com. D) The International Union of Radio Science (URSI) is a foundation Union (1919) of the International Council of Scientific Unions as direct and immediate successor of the Commission Internationale de Télégraphie Sans Fil which dates from 1913. Unless marked otherwise, all material in this issue is under copyright © 2007 by Radio Science Press, Belgium, acting as agent and trustee for the International Union of Radio Science (URSI). All rights reserved. Radio science researchers and instructors are permitted to copy, for non-commercial use without fee and with credit to the source, material covered by such (URSI) copyright. Permission to use author-copyrighted material must be obtained from the authors concerned. The articles published in the Radio Science Bulletin reflect the authors opinions and are published as presented. Their inclusion in this publication does not necessarily constitute endorsement by the publisher. Neither URSI, nor Radio Science Press, nor its contributors accept liability for errors or consequential damages. 2 The Radio Science Bulletin No 323 (December 2007) Editorial Our Papers technological progress in key areas. The technologies that are likely to play key roles in determining the future of wireless Smart antennas are adaptive-array communications are then introduced, and those antennas that adapt their patterns to optimize that will and will not and the reasons why communication. For example, such antennas may again surprise you. Economic and social can focus a beam on a desired mobile device, issues, and issues related to the structure of the while placing pattern nulls on undesired communications industry, are then examined. interference and then dynamically change to Contributions from a series of people who adapt to a different desired mobile device, or to were asked for their predictions are then the motion of the mobile device. One type of summarized. All of this is finally synthesized smart antenna is an electronically steerable into a set of predictions, and the implications parasitic-array-radiator (ESPAR) antenna. ESPAR antenna of those predictions are studied. patterns can be controlled via reactances on the parasitic elements. In contrast to more-common multiple-output As noted, this isnt just a matter of predicting the arrays, ESPAR antennas have a single output port. This development of technology. It also involves predicting makes the signal-processing issues associated with using what areas of scientific research are likely to be needed, and such antennas rather challenging. In the invited what areas are likely to have little impact. Such information Commission C Review of Radio Science in this issue, Eddy can be of critical importance in thinking about future areas Taillefer and Jun Cheng provide a review of current issues of research and development. This paper will form the basis associated with such antennas, and how the signal-processing for one of the General Lectures at the XXIXth URSI challenges are being met. General Assembly, to be held in Chicago, Illinois, USA, August 7-16, 2008. You should definitely plan on hearing The authors begin by providing a very nice and easily it in person! readable discussion of how smart antennas in general, and ESPAR antennas in particular, can be used in a variety of The efforts of Gert Brussaard in arranging for this applications. They also discuss the tradeoffs between Lecture are gratefully acknowledged. multiple-output and single-output antennas in such applications. They then develop a signal model for the ESPAR antenna. They define reactance-domain signal Our Other Contributions processing as the ability of an ESPAR antenna to steer a beam and/or a null in the direction of a source. They then Peter Watson has assembled a substantial set of show how a variety of adaptive-beamforming results can be dissertation abstracts for this issue. In reading them, you can obtained using such signal processing. They explain how find out not only what new research has been done, but have direction-of-arrival estimation can be done using signal an opportunity to experience the ideas of a new crop of radio processing with the one-output ESPAR antenna, and they scientists. describe a variety of algorithms for accomplishing this. As I reported in this column in the last issue, we The efforts of Takashi Ohira, Associate Editor for learned of the sad death of Dr. A. P. Mitra, Honorary Commission C, and Phil Wilkinson in bringing us this President of URSI, just as that issue went to press. Several review are gratefully acknowledged. of Dr. Mitras colleagues have given us a warm and moving account of his life in this issue. Forecasting the future is not usually considered to involve the exercise of much science. However, as William We have an interesting letter to the Editor in this issue. Web demonstrates in his invited General Lecture paper, it It offers some updated estimates for some critical efficiencies can be done scientifically, at least when what is being in the SPS White Paper that appeared in the June issue. forecasted is the future of an area of radio science: wireless communications. He looks at the likely state of wireless communications over the next five, 10, 15, and 20 years. The XXIX General The process is as interesting as the results and I think many Assembly of URSI will be surprised by the results. He begins with an explanation of why prediction is critical, both to business and to those actually doing the science. He then introduces a series of The URSI General Assembly will be held in Chicago laws that serve as guideposts for predicting scientific and next August. The deadline for submission of papers is January 31, 2008, not too long after you will hopefully The Radio Science Bulletin No 323 (December 2007) 3 receive this issue of the Radio Science Bulletin. Information General Assembly headquarters hotel, the Hyatt Regency on how to submit a paper is available at http:// in downtown Chicago, for the ten-day duration of the www.ece.uic.edu/2008ursiga. Information is also available General Assembly, based on double-room occupancy. The there on the URSI Young Scientist program. For this submission deadlines for the Young Scientist program and General Assembly, the local Organizing Committee is for the student paper competition are also January 31, 2008. sponsoring a student paper competition. While the first- through fifth-place finishers in the contest will receive I hope to see you all at the General Assembly! certificates and monetary awards ranging from US$500 to US$1500, all ten finalists will receive free lodging at the Letter to the Editor COMMENTS